Volume 2, Issue 2 --- May, 1992

This is the electronic version of the Stratosphere Newsletter. Occasionally final editing is done to the actual layout of the newsletter and spelling checks, and other corrections may not make it into this edition. The content is complete (except for graphics).


President's Corner

For me, EOSS-5 was an exciting project. While everything was not as successful as we had hoped, we learned a lot from it and will do even better the next time. I was especially delighted for the success of the IAAS stabilization experiment. Everyone did an excellent job pulling this project together. Already many of the problems experienced on EOSS-5 have been corrected, and we look forward to proving them on EOSS-6 now targeted for May 30th.

The May meeting will be important because the final details of the EOSS-6 or Humble Telescope II project will start to come together. Because this will be another LARGE balloon, we are going to need some extra help. There will be lots of small manageable jobs to be performed, so dive in and give us a hand.

Memberships this year are approaching that of last year but our goal is a 50% increase. So even if every other one of you bring in one new member, we can still make our goal. How about it, don't you know someone that would like to join us and participate in our exciting projects?

I hear talk that there are some good donations out there just waiting for our non-profit status to be approved by the IRS. Well, we are better than half way through the evaluation period and so far no hitches. I believe by June 1st, we should have our approval. I hope all that talk turns out to be real. We have several projects including the upgrade of our shuttle box and ground station equipment that will require additional funding.

Tom Isenberg has been doing an outstanding job getting our student membership and schools involved in our projects. He could certainly use some help now. As I see it, this is one area in our organization that is going to get busier and busier. Let Tom know you appreciate his efforts and volunteer to join his Education Liaison staff.

That's it for this month. Hope all you like the new look of "Stratosphere" and thanks to Tim Kelliher for his efforts as the new editor.

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Education Notebook

"Promoting Science and Altitude through Amateur Radio and High Altitude Balloons"

An electrical engineering major doing editorial work for "Stratosphere"??? Come on now, have we gone to the dogs in education? No, I think not. Tim Kelliher is just honing the writing skills he will need in writing all those technical reports his future job may require. Good job Tim!

Heritage High School students got a big jump on a future EOSS project by building their own Quad antennas. Although the ham club will be setting up the ground station, Rick Volp and Erik Lawson made their own Cubical Quad Antennas and have participated in some "fox" hunts. In the future, EOSS plans to help those students who are interested in transmitter hunting build antennas and have special student "fox" hunts to prepare them for the field. Way to go guys!!

Eleven year old Kristen Tobiassen KB0JSF and her father Tom N0BZ worked together on the April 11th launch by providing radio coverage on the 220 MHz interlink to the field. Kristen is an EOSS member and hopes to upgrade to Tech soon. Welcome Kristen on the 147.225 MHz repeater on the Tuesday evening net. We're proud of you Kristen!!

What can be said about the IAAS and all the education they get with their involvement with EOSS? If we were to list all the areas of educational sources we have, they have pursued it and expanded those areas. Our student contacts Suzanne Wahrle, Mike Ditto, and Chris Rand have done a super job in keeping their group busy with EOSS projects. Just THANKS!!

New blood in the ranks with the addition of Cherry Creek and Smokey Hill High Schools. The May 2 contest took a turn for the better by including these two schools. The physics needed to provide a payload that lands vertically is great food for thought. Look for these students to be helping at our next launch with Richard Shaw, WB5YOE, and the Paratrak program. A real opportunity to visit the weather service. Welcome aboard!!

Eaglecrest students will find time to break away from their radio studies to provide plotting information during our next launch. A repeat performance for this group, who did an outstanding job during the January 4th launch. They should have a ham club started soon with licensed radio operators. Glad you're back!!

Green Mountain High School will, again, run the experiment that will take magnesium pictures of the sun. The project, named Humble 2, will fly on May 30th. These students have used data from the last launch to improve the chances of success to get their pictures this time around. EOSS is happy we are working with you GMHS.

Education futures include working with the Longmont High School district through the efforts of the Longmont Amateur Radio Club.

Cherry Creek High School has proposed a radiation (BETA waves) versus altitude experiment for next year.

Work books will be in the works as a learning tool.

As a tweener (between launch project) we hope to get those students interested in "fox" hunting to build some antennas and do some student hunts.

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Ground Reflection

Thanks in this newsletter go to two guys that have helped EOSS and have been generous with their time and property.

First, thanks to Rich Volp, N0PQX, an EOSS member and Heritage Student who took over and did a great job with the ground station for EOSS-5. Also, public thanks are due to Bud, owner of Electronic Bits and Pieces (Colfax & Iola in Aurora, Colorado). Bud has been very generous with miscellaneous parts, as well as his contribution of the LORAN-C equipment.

We will be designing a project to try to improve the TV downlink and will announce our plans on an upcoming net. Rich and I have a lot to learn about ATV and will be counting on help from some of you experienced ATV operators. Thanks in advance.

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EOSS-5, Flight Results

Edge of Space Sciences, (EOSS) Spacecraft Stabilizer & VOR Experiment
April 11th, 1992


On April 11th the Edge of Space Sciences (EOSS) team launched EOSS-5 from Clements Park in Jefferson County, south west of Denver. Three scientific experiments were conducted by student members as the balloon rose through 106,000 feet. Again the EOSS Team headed by Jack Crabtree, AA0P was successful with the launch, control and recovery of the spacecraft.

Education Team

Tom Isenberg, N0KSR, and his team of students from Cherry Creek High School, journeyed to the National Weather Service to acquire winds aloft information for their prediction program. Students selected the appropriate winds, entered the data and predicted the flight and touchdown of the payload to be due east, 102 miles. Congratulations to this team as their prediction was only 14 miles from the actual touchdown, permitting the recovery teams to focus on a very small area.

Amateur Radio Activities

Amateur radio continues to play a significant role in EOSS missions. Crisp, P5 amateur television video on 426.25 MHz was collected by a ground station operated by Rich Volp, N0PQX as we watched the stabilization experiment being conducted. Operating in the field, Bob, W6ORE, and Neil, WD0ADU, were able to capture and record quality ATV video from the payload during the full descent. Recording the touchdown was a first for any EOSS mission which tend to fly 100 miles and are over the horizon and out of view of the base station at the launch site.

Net Notes

The public relations nets were conducted by Eileen Armagost, WD0DGL and Tim Armagost, WB0TUB, on two and forty meters respectively. Beacons were heard as far away as Lincoln, Nebraska, 560 miles to the east. Ann Trudeau, KA0ZFI, worked with the press and is preparing news articles for various magazines.

C.R.A. Portable Repeater

In support of the 20 recovery teams in the field, John Schwartzberg, N0GII, and the Colorado Repeater Association (CRA) once again performed with stellar effectiveness. The CRA set up their magnificent portable repeater near the town of Bovina, about 15 miles east of Limon to provide a link into Denver. EOSS appreciates the efforts of the CRA team and recognizes their invaluable role in these missions.

Flight Path

The flight path was in an eastward direction from the launch site, rose to 106,000 feet (20.8 miles), flew 92 statute miles and landed 2 hours and 20 minutes later 35 miles NNE of Limon, Colorado.

Recovery Teams

Recovery teams were masterly directed by Ed Wade, KA0ZAS, who plotted and directed teams to a record payload recovery time of 11 minutes after touchdown! A new plotting program, written and operated by Paul Ternlund, WB3JZV, was trialed during this mission and proved to be another very useful tool for the recovery teams.

Few people have ever seen the descent of an EOSS payload and Greg Burnett, K0ELM, and his keen-eyed navigator, Eric watched the last 15,000 feet and observed the performance of the bright orange parachute built by Merle McCaslin, K0YUK.

Experiment Results

Stabilization Experiment Results:

Principal Investigator was Suzanne Wahrle of the International Association of Astronomical Studies (IAAS). Suzanne and Merle McCaslin controlled the vane stabilization experiment. Suzanne was extremely impressed by the results. By changing the position of the vane, they were able to make the payload spin either way, or stop the payload's rotation. They were able to target a lake and keep the CCD camera on the lake by manipulating the controls. Suzanne says, "It was very thrilling" as the images obtained by the CCD camera were recorded. As in every experiment, all does not go well as the CCD camera and vanes would not accept commands during the latter part of the mission, so the effectiveness of the vanes higher in the atmosphere is still unknown. Suzanne speculates that they still work the same, just not as efficiently. Suzanne says, "Thanks again for the wonderful opportunity. We really enjoyed it! Maybe we can launch an experiment again sometime in the future."

VOR Experiment Results:

Principal Investigator is the payload lead, Mike Manes, W5VSI, of EOSS. The intent of the VOR Experiment was to use aeronautical signals which would be transponded to the ground via the ATV sound channel. Signals would be decoded on the ground and a determination could be made as to the effectiveness of locating the balloon during flight. However, the audio channel on the ATV downlink did not provide the fidelity required and only a few good readings were recorded. Mike has several ideas to improve performance for the next flight.

Tracking Beacon Experiment:

Principal Investigator was Neal Tenhuzen, WB0ADU, of EOSS. The intent of the experiment was to employ a new, additional beacon to transmit on 147.555 MHz. This beacon was designed for the recovery team to use for direction finding activities. The beacon has a one second beep with a CW identifier every 10 minutes. The antenna is vertically polarized and transmit power is 250 milliWatts. Duty cycle is 20 seconds on and 10 seconds off. This experiment suffered a power problem and the secondary beacon on 144.340 MHz was commanded to full duty cycle for tracking purposes. Neal reports this experiment has been redesigned and will fly on the next mission.

Payload Release Experiment:

Principal Investigator was Jack Crabtree, AA0P, of EOSS. A commandable hot nichrome wire cut-down system to release the payload from the balloon prior to balloon burst. The release was successful upon command and the payload fell away from the violent burst of the balloon particles which previously have fouled the parachute system.

Thanks to the hundreds of volunteers who help make Edge of Space Sciences missions such a success.

Next Mission

May 30, 1992, EOSS-6 will fly the Humble Solar Telescope II. Students will take photos of magnesium II storms on the sun. Watch packet and the Comm Post BBS (now Filebank BBS) for more details.

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Notes from Around the Globe

I would like to share a note from EOSS member Ev Wittig, WB7VNF in Colorado Springs who attended the April 11th launch with his entire family. Congratulations to our newest scientist, Erik Wittig.


My son Erik, placed in the "Exceptional" category with his EOSS entry on Temperature versus Altitude. He was also awarded a special award by McDonalds for Science Excellence of the project. Several of the judges wrote very flattering remarks about the project. Erik explained to each judge about EOSS, most all had never heard of it but all expressed interest.
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As the Science team lead for this launch I have not truly voiced my opinion as to the successes or failures of this mission. I would like to do that now.

Much has been said about this flight, from total flop to complete success. I have spent much of the past month thinking about what happened and what was learned. On launch day the mood was grim after the "crash" and I was very disappointed, there was but a glimmer of hope that the damage was not extensive. When the payload was recovered however, all hope was lost. Kevin, myself and many others had spent the better part of five months putting that payload together and it was disheartening that the primary mission was not accomplished.

The next day I was listening on 2 meters and was astonished (for lack of a better word) at what I heard. Plans to launch another as soon as possible were being made. It made me realize that the primary mission did not fail, rather what everyone perceived as the primary missions was just wrong. One day when we were building the payload, Jack, AA0P, and Mike, W5VSI, said to me "... this group (EOSS) was formed to have fun, this is a hobby." This rings to heart now, the idea here is not to gather scientific data, it is to have fun and learn something while doing it. This is the primary mission of every launch. If everyone has fun and learns something then the mission is a success and that is precisely what happened. Let's not dwell on what didn't happen, instead, let's rejoice about what did happen. We pulled off a feat that not many people could have.

I would like to extend my extreme gratitude to everyone involved and I would especially like to thank the following for their involvement above and beyond all expectations: Mike Manes, Jack Crabtree, Merle McCaslin, Dave Clingerman, Bob Schellhorn, Greg Burnett and all the fox hunters and my good friends and partners Kevin Keaney and Norm Sitter.

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The Vertically Polarized Gain Array

This piece could even be titled, "Olde Antenna Lab" takes up the challenge, again. According to my ledger a considerable amount of groups are flying the "Little Wheel" antenna for their ATV radiator. And, I co course am very happy that the "Little Wheel has enjoyed such success and enhanced the enthusiasm of ATV Ballooning, kiting, rocketry, RCing and not quite yet Frisbiing. However, not everyone in the nation or the world has chosen to propagate their video (ATV) signal in the horizontal plane. Recently here in Denver the local ATV repeater group, Western Vision Network (WVN), has after an exhaustive study (five minutes) decided to go to a vertical input on the repeater. So up the towers and into the attics we all went to put a 90 degree twist on the tails of our 70 cm yagiis so we could once again access the repeater. Now, in order to capitalize on the maximum amount of ATV participation during the local balloon launches, Edge of Space Sciences, Inc. (EOSS) had to request their technical committee come up with a spacecraft antenna that would be vertically polarized, light weight and perform considerably better than a "rubber duck". As Chief Scientist/ Technical Committee Chairperson of EOSS, without hesitation or reservation, I elected again to take up the challenge and launched into a rather extensive research program to design, create and test a vertically polarized, gain array and still meet a launch date of April 11th, 1992.

The research went something like this; KISS (Keep It Simple Stupid) Method - what's first and available? The stinger, the spike, the quarterwave length monopole, the old sewerpipe type monopole was considered. All semi-radiating dummy loads, to one degree or another. Even though, mathematically proven do have 3 dB over a dipole, the Brewster angle is too great to place the main lobe maxima on the horizon when the edge of space is encountered. They exhibit narrow bandwidths due to the high Q (inductive reactance to DC resistance ratio). Physically, if affixed rigid to the spacecraft they are subject to and influenced by spacecraft dynamics, then you have the polarity characteristics that resemble the tail of a Stingray in potion. How about a 5/8 wave or a coaxial colinear to solve the problem. Not quite, similar problems to those previously presented will be experienced. Given however, the Brewster angle will be lessened and the energy will be more on the horizon. They are inefficient as they burn up power; one in the matching scheme the other in its dielectric. Any light weight "spike" type of radiator will pendulum. Sure there are techniques for reducing the penduluming but they involve added weight which isn't acceptable. The accounts I've read of ATV balloon operations that have used stingers and the such for their ATV signal radiators indicate it's definitely not the way to go. How about a solitary folded dipole, in an effort to gain the bandwidth required to properly propagate an ATV signal. Same problems with stability as the monopole, plus the added problems of mounting vs. feeding. For example; mount it on the side of the spacecraft and you shadow the opposite side and seriously hamper reception on the two adjacent sides. Dangle it below the spacecraft and the pattern will be distorted by the feed line. How about employing a pair of folded dipoles for balance and reducing the feedline effects as moving the feedline far enough out of the pattern so as not to effect either radiator? Then a nice bi-directional array has been created that will twist and turn on the feed line and drive operators nuts that are trying to copy and/or record the video, as the signal strength goes from P0 to P(n) and back again.

The folded dipole, to me, still had some interesting features that I thought might be pressed into service if I can come up with the right combination/configuration and win approval of the EOSS technical committee for that matter the EOSS membership at large. With calculator in hand an investigation was undertaken to determine what sort of design could be conjured up that would allow the basic folded dipole to produce an omni-directional pattern in the horizontal plane with a predominantly vertical E-field. Considerable consideration was given to a configuration that would shift the high current node inherent at the base of the radiators such as a quarterwave monopole or 5/8 wave radiator which burns up a considerable amount of power in heating the groundplane. The folded dipole was examined from the very basics such as optimum material diameter of the top and bottom radiating elements. Similar diameters allow a 4:1 impedance transformation and present a terminal impedance of 288 ohms. A departure definitely had to be made from the pair of folded dipoles because as previously stated; the array would be bi-directional; however, the E-plane pattern characteristics are attractive due to balun perturbation. Why not three radiators around a center hub and stand them off by a 1/4 wave? That way the pattern would become more than bi-directional and the feed impedance would be a third of the folded dipole by itself. The feed impedance of approximately 90 ohms would be easy enough to match to a 50 ohm with a 1/4 wave length of RG-62 (93 ohm) or a balun of sorts like a bazooka (coaxial Q-bar). The geometric mean of 50 and 90 is 67. A 1/4 wave length of 75 Ohm coax would probably suffice. However, the bazooka would provide some structural integrity to the array and therefore could not be flexible. Creating a 50 ohm air line that is 1/4 wave at 70 cm was only a matter of turning the crank on the coaxial transmission line equation.

Testing the array was accomplished by first sweeping the device with a Texscan UHF Sweep Oscillator, Wiltron SWR Bridge and presenting a visual indication of the bandpass on an HP-1743 Oscilloscope, using it in the X vs. Y mode. More slight bending had to be done to bring the 1:1.0 portion of the curve to the portion of the spectrum where I wanted it, (425-431 MHz). Resonance at the desired bandwidth accomplished, next the E and H plane pattern measurements and last but not least the gain determination.

The National Bureau of Standards (Boulder Labs) where I am employed has several antenna ranges that are available to me. The election was to use the outside range for my testing as it is less scheduled than the others this time of the year, (March). The center of the rotational platform is sufficiently far (30 meters) from the source to make my measurements definitely "far field". After calibration the array was rotated in the "H" plane to ascertain any discrepancies such as deep nulls anyplace in the 360 degrees of coverage. The smoothed pattern was so smooth that the transition from element to element was barely discernible (less than +/- 1.5 dB). Next the array was turned in the "E" plane and what was anticipated and hoped for of the pattern became reality. In the design stage it was thought that the balun would act as a reflector to the upper portion of the elements. It did, the pattern that was presented was a skewing of the main lobe by some twenty degrees and causing some side lobes at the top of the pattern that were not evident at the bottom. The envelope appeared to very much resemble a classic cosecant squared relating that is very desirable of search radars on airborne platforms. A hard copy of both E and H planes were plotted.

(It is definitely my sincerest hope that the "reinvented 1/4 wave stub" that was flown as the ATV radiating device on the EOSS April 11th 1992 launch will not be presented to the student membership as "NEW SCIENCE".)

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